Taste buds are complex multicellular endorgans essential for detection of taste. The cells of a taste bud distinguish between the nutritious and the potentially toxic, and communicate this information to the taste nerves innervating them. Despite recent advances in understanding the molecular signaling underlying taste transduction, a complete understanding of cell--cell interactions and transmission of information to the peripheral nervous system is lacking. We propose to use a newly invented technology, serial blockface scanning EM, to generate a complete 3D picture of taste bud structure. This will permit detailed analysis and determination of several key features including: 1) whether individual nerve fibers make functional contact with more than one cell type in a bud, 2) whether Type I cells fully separate the other cell types or whether there is potential for functional connections between the molecularly different chemosensor elements, and 3) whether atypical mitochondria are unique organlees lying only at points of specialized contact between taste cells (for bitter, sweet and umami) and nerve fibers. This greater understanding of the detailed structure of taste buds will help investigators formulate data-based hypotheses regarding functional interactions between the different cellular elements and a more clear understanding of how taste information is transmitted to the nervous system.